Physiotherapy in Patients with Stress Urinary Incontinence: A Systematic Review and Meta-analysis

Physiotherapy is the most commonly used treatment for stress urinary incontinence including pelvic floor muscle training, biofeedback, and electrical stimulation. This systematic review evaluated the effects of physiotherapy in patients with stress urinary incontinence compared with no treatment, placebo, sham, surgery, or other inactive control treatments. MEDLINE (via PubMed), The Cochrane Library (CENTRAL), Embase, Scopus, Web of Science, PEDro, and Trip Database were explored using applicable vocabularies for all English and Persian language investigations released from inception to January 2021. On one side, trials including physiotherapy of pelvic floor muscle training, biofeedback, and electrical stimulation and on the other, either no treatment, placebo, sham, surgery, or other inactive control treatments were included. Studies were assessed for appropriateness and methodological excellence. Two authors extracted data. Disagreements were resolved by a third opinion. Data were processed as described in the Joanna Briggs Institute Handbook. Twenty-nine trials with 2601 participants were found, but only 16 were included because of data heterogeneity. The results showed that physiotherapy interventions are better than no treatment in terms of urine leakage, but no difference was found for urinary incontinence severity. Also, physiotherapy showed favorable results over comparison groups for International Consultation on Incontinence Questionnaire, pad test, pelvic floor muscle function, and improvement outcomes. This systematic review supports the widespread use of pelvic physiotherapy as the first-line treatment for adult patients with stress urinary incontinence.


Introduction
According to the Sixth International Consultation on Incontinence (ICI), stress urinary incontinence (SUI) is the unconscious loss of urine during physical exertion, sneezing, and coughing that often results in impaired quality of life (QOL), personal hygiene, and social relationships. 1 The prevalence of SUI is 24.8% in the United States 2 and 57.7% in Iran. 3 In 25% of patients, SUI has negative impacts on various aspects of life including social, psychological, occupational, physical, 4,5 and sexual activities. 6Besides, UI has a substantial financial impact on people's lives. 7veral tests are used to diagnose and monitor urinary incontinence (UI), either subjective or objective. 8The International Consultation on Incontinence Questionnaire on Female Urinary Tract Symptoms (ICIQ-FLUTS), the Urogenital Distress Inventory 6 (UDI), the Incontinence Impact Questionnaire-Short Form (ICIQ-SF), 1,9 and the King's Health Questionnaire are the most frequently used tools to assess incontinence impact on daily life. 10As functional tests, physical assessment, dynamometer, electromyography, ultrasound and magnetic resonance imaging, 11 a bladder diary, 12 and pad tests 13 are regularly used in UI evaluations.

Fariba Ghaderi 1
Ghazal Kharaji 2 Sakineh Hajebrahimi 3 Fariba Pashazadeh 3 Bary Berghmans 4 Hanieh Salehi Pourmehr 5 At present, there are surgical and conservative interventions for SUI.Physiotherapy is one of the most prescribed conservative treatments.Pelvic floor muscle training (PFMT), biofeedback (BF) therapy, electrical stimulation (ES), and vaginal weights are some of physiotherapy options. 14lvic floor muscle training is known as one of the first-line options for SUI. 15 Pelvic floor muscle exercises (PFME) are used to increase (maximal) strength, endurance, timing, explosive strength, and muscle coordination.Pelvic floor muscle training includes passive, active-assisted, active-resisted, and simple contraction exercises with or without ES, BF therapy, and vaginal weights.9,16 Also, PFMT can be prescribed home-based or supervised, which are different in terms of adherence and compliance.17 Moreover, PFMT is used in combination with stabilization exercises to reduce SUI and lower back pain (LBP) symptoms in pregnant 18 or elderly women. 19Biofeedback therapy is an adjunct to PFMT, a technique assessing physiologic processes of the body, which can be used to learn control some of body's functions, such as activity of the pelvic floor muscles (PFMs).In the case of SUI, depending on the type of BF (EMG, pressure, or ultrasound), BF therapy makes patients aware of the activity of their PFMs through electromyographic activity, manometric squeeze pressure, or bladder base displacement.20 The scientific evidence for BF therapy in SUI treatment is still inconclusive probably due to different treatment methods (frequency of treatment sessions, type of contraction, and duration of contraction) in various studies.21 Electrical stimulation is another treatment option for SUI that includes suprapubic, transvaginal, sacral, and tibial nerve stimulation.22,23 Vaginal weights are used to train PFMs by inserting a weight into the vagina and asking the patient to hold it there by contracting the PFM.Once the patient succeeds to hold a certain weight, the next step is to replace the weights with a similar-sized but heavier one.20 To the best of our knowledge, few systematic reviews with metaanalyses have investigated the effectiveness of PFMT, alone or in combination with BF, ES, vaginal weights, or other types of exercises.9,21,24 The lack of consensus on the effects of these treatments and absence of an updated systematic review since 2018 24 necessitated this systematic review.Therefore, this systematic review evaluated the effects of physiotherapy on SUI, episodes of urinary loss, quality of life (QOL), and muscle strength in adult women with SUI, compared with no treatment, placebo, sham, and surgery.

Inclusion Criteria
Participants: Studies that included adult women with SUI or mixed urinary incontinence with SUI as a dominant factor.
Intervention: Physiotherapy involving PFME with or without BF, education and information, surface and intracavity ES, dynamic lumbopelvic stabilization exercises, magnetic stimulator, neuromuscular external stimulation device (NMES), and bladder training (BT).
Comparator: No treatment, placebo, sham, surgery, or other inactive control treatments.
Outcomes: Studies using measures such as pad test, Oxford Scale, PERFECT scale, manometry, EMG-BF, urodynamic investigation, UI leakage episodes, UI improvement based on validated measurements (ICIQ-FLUTS, UDI-6, ICIQ-SF, Patient Global Impression of Improvement (PGI-I)), and patient satisfaction were assessed to be included.Only randomized controlled trials were included.Studies published in English and Persian languages from inception to July 2021 were considered for inclusion.

Material and Methods
This investigation was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 25 statement and the JBI methodology for systematic reviews.Besides, the study protocol was registered in PROSPERO registry for systematic reviews (CRD42021233176).

Search Strategy
Published and unpublished evidence were searched.A three-step strategy was applied.First, a primary search was performed in PubMed and titles and abstracts were reviewed.Therefore, a comprehensive search was used using all identified keywords and index terms on January 2021 across MEDLINE (via PubMed), The Cochrane Library (CENTRAL), Embase, Scopus, Web of Science, PEDro, and Trip Database.Moreover, gray literature was searched in ProQuest (for theses), Google Scholar (for unpublished studies), and clinicaltrials.gov(for registered clinical trials).Finally, the reference lists of all selected documents were explored to find extra trials.The full search strategy for MEDLINE (via PubMed) and Embase is provided in Appendix I.

Study Selection
All investigations were added into EndNote X7.1 (Clarivate Analytics).Duplicate studies were automatically removed.Titles and abstracts were investigated by 2 authors separately by considering the inclusion criteria.Thereafter, full texts of selected trials were read carefully.The reasons for excluding some investigations are illustrated in Appendix II.Any disagreements between the 2 authors were resolved by a third opinion.

Assessment of Methodological Quality
Primarily included investigations were judiciously evaluated by two authors using tools from the Joanna Briggs Institute for experimental and quasi-experimental studies to determine methodological biases.Studies were categorized as low (11-13), moderate (8-10), and high risk (lower than 8) according to the consensus expert opinion.Studies with high risk of bias were excluded.

Data Extraction
Data were extracted by two independent authors, using the modified standardized JBI data extraction tool (Handbook of JBI for interventional Systematic Reviews).Extracted data included authors and year of publication, intervention details including duration of treatment sessions and study, and sample size.Authors were contacted to request missing or additional data.Furthermore, in the case of unpublished trials, an e-mail was sent to the corresponding author(s) to ask whether the investigation was published.If no response received after 3 e-mails, the study was not included.

Data Synthesis
Where possible data were pooled using STATA v.14 (StataCorp, California, USA).Effect sizes, expressed as odds ratio (for categorical data), and weighted mean differences (for continuous data) and their 95% confidence intervals were calculated.Heterogeneity was evaluated by I 2 tests.Statistical analyses were run using the random effect model. 26Subgroup analyses were performed where there was adequate data to examine based on manometry (cmH 2 O-mmHg) and pad test (long or short term).Publication bias was not assessed because there were less than 10 included studies.Despite that, tables and figures were designed when statistical pooling was not possible to help for further assessments.

Results
Study InclusionTotally, 1773 citations were identified by electronic search, hand search, and reference check.After removing duplicates, 1266 studies remained for the screening process.By reviewing titles and abstracts, 62 studies were selected.In the full-text selection, 23 studies were excluded.Finally, 36 studies were included for the critical appraisal process.Additional information on selection process is presented in the PRISMA flowchart (Figure 1).

Summary of Included Articles
Methodological Quality: Thirty-six eligible studies were critically appraised by the JBI appraisal checklists to assess possible biases.Twenty-nine studies were moderate (8-10 positive criteria) or high quality (11-13 positive criteria), and 7 were low quality (<8 positive criteria), which were excluded.Evaluation results of eligible studies are presented in Table 1.

Grade
Based on the grade, studies entered the meta-analysis with 5 main outcomes, and there was serious inconsistency between them (Table 3).Therefore, the grade of recommendation of included studies in meta-analysis was very low in all 5 outcomes.There are a large number of RCTs regarding the effect of physiotherapy and pelvic floor exercises on SUI.Despite the fact, there is much heterogeneity in the intervention and control groups owing to different tools and methods of measuring the consequences.

Discussion
The main objective of this systematic review and meta-analysis was to analyze RCTs that investigated the effects of physiotherapy techniques such as BF, PFMT, and ES or surgical treatments and so on on episodes of urinary loss, QOL, and muscle strength in SUI patients.
The main finding was that physiotherapy treatment successfully improves both subjective and objective measures in women with SUI compared with control groups or other treatments.However, owing to heterogeneity of studies, there is lack of consensus about appropriate treatment parameters for women with SUI.
Our analysis included 3 studies related to incontinence severity 17,42,45 presenting favorable results for physiotherapy treatment over comparison groups.The effect size estimated for 2 studies 42,45 supports the positive effects of physiotherapy but effect size of 1 study 17 was small and not significant.Huge variation in PFMT programs, varying from supervised PFMEs 42 to mobile app 45 and home-based stabilization exercises with focus on PFMs, 17 and study populations including women with postnatal SUI 17 and elderly population 42 were found among the selected studies.Despite these differences, supervised and unsupervised PFMT were always superior to the control intervention.
Previous studies reported that combined BF and PFMT have multiple effects, including increased trophism and neuromuscular function of the pelvic floor muscles, 58 which is effective in improving urethral closure during increase of intra-abdominal pressure. 59However, improvement analysis after physiotherapy treatment including PFMT 31,35,43 and BF 48 compared with control groups showed nonsignificant results.Adding BF to the PFMT did not have any additional advantages in some investigations 47,48 but was better than using BF alone in another study. 55e This study indicated that non-face-to-face PFMT may be an effective treatment for SUI. 45Ghaderi et al 31 reported that PFMT focusing on strength, endurance, and progression of training in different positions may be a safe and effective treatment for women with all kinds of UI.
Altogether, it can be interpreted that a progressive and intensive PFMT program focusing on endurance and strength of PFMs in different positions is key in the conservative treatment of SUI.It seems that in most effect studies of physiotherapy for urinary incontinence, PFMT has been studied.Besides, the effect of adding other treatment modalities to PFMT has been investigated widely. 28,31,32,49,52The superiority of PFMT was indicated comparing intensive and supervised PFMT, with any other modality or method as control group. 17,28,32,34,37,41,45Adding stabilization exercises to PFMT increased the effectiveness of training in the long run, 49,50 but adding adductor muscles exercises to PFMT did not show any additional effects. 52reover, individualized PFMT with a supervising physiotherapist was preferred when comparing PFMT as home training, only based on previous training and education or using a mobile application with individualized and supervised PFMT. 31,42However, in terms of costeffectiveness, Internet-based training or the use of mobile apps may be better than no treatment. 28,34,38,60Using an application to do exercises 38,45 or remote-control exercises 36 showed better results than home-based exercises without any supervision or no treatment. 38Treatment sessions alone without supervision of exercises did not replace supervised sessions or change adherence of patients to treatment. 40erall, PFMT is an effective first-line treatment modality for SUI.If possible and affordable, performing individual PFMT under the supervision of a well-trained physiotherapist at least once a week is the treatment of choice.Biofeedback therapy as an adjunct to PFMT may be useful in patients with no or insufficient awareness of their PFMs. 28,32,47[56] However, if supervised physiotherapy is not available, it is recommended to perform home PFMT using educational pamphlets or online applications. 36,38,44,45mitations and strengths There are some limitations to our systematic review that should be acknowledged.This study included articles only in Persian or English.Also, included studies were highly heterogeneous in terms of study population, treatment protocol, and duration of treatments.Accordingly, there is a need for a well-designed study with more consistent treatment protocols and study populations.
In fact, the results of this study should be implicated with caution.However, the strength of our study is that almost all types of physiotherapy treatments, including PFMT, BF, and ES, were evaluated.Based on this review, physiotherapy for SUI could be updated after 8 years. 20

Conclusion
Although physiotherapy treatments showed significant results over comparison groups, there was considerable statistical heterogeneity among the eligible studies.Further RCTs should assess long-term effects of physiotherapy treatments in women with SUI.Moreover, further studies should investigate which treatment parameters are more practical and effective.Finally, it is recommended to use PFMT as a first-line treatment in women with SUI to improve both subjective and objective outcomes.Biofeedback therapy also can be used as an adjunct to PFMT to improve treatment results.Results of using ES in women with SUI are not conclusive and more studies are required.

Figure 1 .
Figure 1.Search results, study selection, and inclusion process.

Figure 2 .
Figure 2. Difference between physiotherapy interventions and no treatment according to the ICIQ-SF.ICIQ-SF, International Consultation on Incontinence Questionnaire-Short Form.

Figure 3 .
Figure 3. Difference between physiotherapy interventions and no treatment according to pad test.

Figure 4 .
Figure 4. Difference in urinary incontinence severity according to the ICIQ-SF between physiotherapy and comparison groups.ICIQ-SF, Incontinence Impact Questionnaire-Short Form.

Figure 5 .
Figure 5. Difference in urinary incontinence severity according to pad test between physiotherapy and comparison groups.

Figure 6 .Figure 7 .
Figure 6.Difference in PFM function according to manometry between physiotherapy and comparison groups.PFM, pelvic floor muscle.

Table 1 .
Critical Appraisal of Eligible RCTs

Table 2 .
Characteristics of Included Clinical Trials Author

Table 2 .
Characteristics of Included Clinical Trials (Continued)

Design Total Sample Size/Study Subgroup Group Characteristics Sample's Number (Mean Age)/Intervention Description Study Duration Methods for Outcome Measurement Control Intervention
BF, biofeedback; ES, electrical stimulation; ICIQ-LUTSqol, International Consultation on Incontinence Questionnaire-Lower Urinary Tract Symptoms, Quality of Life; ICIQ-SF, International Consultation on Incontinence Questionnaire-Short Form; ICIQ-UI SF, International Consultation on Incontinence Questionnaire-Urinary Incontinence, Short Form; IEF, incontinence episode frequency; LBP, low back pain; MVC, maximally voluntary contraction; PFM, pelvic floor muscle; PFME, pelvic floor muscle exercises; PFMT, pelvic floor muscle training; PGI-I, Patient Global Impression of Improvement; QOL, quality of life; SUI, stress urinary incontinence; TVES, transvaginal electrical stimulation; UI, urinary incontinence.
results mentioned above for subjective and objective outcomes of incontinence severity, pad test, PFM function, and improvement may indicate favorable response regarding the physiotherapy treatments despite high level of heterogeneity.

Table 3 .
1evels and Grades of Included Studies -SF, International Consultation on Incontinence Questionnaire-Short Form; PFM, pelvic floor muscle; SMD, standarized mean difference.1Considerableinconsistency; 2 total event is less than 300. ICIQ